aoc2024day2.py

# === Parsing ===

reports = []
with open("input.txt", "r") as f:
    reports = [
        [int(num) for num in line.split()]
        for line in f
    ]

print(reports)


# === Part 1 ===

from itertools import pairwise

safe = 0
for report in reports:
    direction = 0  # Positive means up, negative means down
    for left, right in pairwise(report):
        if not 1 <= abs(left - right) <= 3:
            break
        if direction * (right - left) < 0:
            break
        direction = right - left
    else:
        safe += 1

print(safe)


# === Part 2 ===

from itertools import pairwise


def is_safe(report, direction):
    for left, right in pairwise(report):
        if not 1 <= abs(left - right) <= 3:
            return False
        if direction * (right - left) < 0:
            return False

    return True


safe = 0
for report in reports:
    this_safe = is_safe(report, report[1] - report[0])
    idx = 0
    while not this_safe and idx < len(report):
        smaller_report = report[:idx] + report[idx + 1 :]
        this_safe = is_safe(
            smaller_report,
            smaller_report[1] - smaller_report[0],
        )
        idx += 1
    safe += this_safe

print(safe)